At present, there are not over-voltage protection for the input setion in most of the chargeable electronic cigarettes and the accessories thereof (such as the electronic cigarette cases and the electronic cigarette chargers). For example, when the charging voltage being added to 10V, an electronic cigarette, whose charging interface only can receive an input of 5V, may damage because of having no over-voltage protection and this high voltage, and more seriously, may cause fire accident.
Although some electronic cigarettes and the accessories thereof use varistors or TVSs to provide the over-voltage protection for a short time, the varistors and TVSs can't bear if the high voltage last for a long time. So the electronic cigarettes and the accessories thereof can't be protected from the long-lasting high input voltage.